Patricia Marcos is a young woman who lives with her family in a fictional town in the outskirts of Madrid, Blancaró. The night she turns 18 Patricia plans to go out with her cousin, Cris, to parties at the neighboring village. After arguing with her mother, Lola, about what time she needs to be home by, Patricia gets permission from her father, Alfredo, to return home later than her mother expects. However, she never returns home, which mobilizes her family and the Civil Guard to search for her as a missing person . As the investigation and searching continues a number of previously unknown details of Patricia and the neighborhood come to light.
As more and more time passes, the parents of Patricia desperate to get answers. When the father of Patricia gets a hidden diary, a mysterious character named Eloy becomes the prime suspect in the case.
The focus of the investigation into the disappearance of Patricia gives a shocking turn to someone close to the family of Mark. In addition, a stranger appears with valuable information.
A key piece of evidence is not what it once seemed, forcing Lt. Official Andrún Sierra and begin again the investigation.
The Civil Guard found some incriminating evidence against their prime suspect, Eloy Kasan. Meanwhile, reports of the disappearance of another young woman severely complicate the case.
Patricia's body has been found lifeless in the swamp. The Civil Guard does the autopsy and follows all the leads to discover the murderer. The Marcos family faces their new situation.
Diego, Patricia's brother, is arrested as a suspect when trying to flee from Blancaró on the day of the funeral. Lieutenant Andrun discovers the clasp of Patricia's pendant and a bloodstained stone at the Jinera polygon, confirming that it is the scene of the crime.
Unable to bear the terrible events happening around him, Alfredo lies unconscious on the living room floor. His sudden illness will disrupt the family's plans. With her husband in the hospital, it will be Lola herself who makes a discovery that will make her wonder once again to what extent she knew Patricia.
After discovering that Beatriz knew of the relationship that her boyfriend César had with Patricia, the young woman becomes one of the main suspects. Despite her efforts to disprove any involvement in the murder, Lieutenant Sierra will not stop until the girl confesses everything she has hidden so far.
Warned by Alfredo, Lieutenant Sierra and his team discover that Richi's alibi the night of Patricia's disappearance is not as solid as they had originally thought. With his girlfriend Vanesa making veiled accusations, and with the latest discoveries pointing to the bar, the bartender becomes the prime suspect.
We join the Civil Guard five years after the case was resolved Patricia.
Sierra and Laura return to Blancaro to investigate the case of Cris's kidnapping. Everything indicates that an accomplice of her father has been the one who has kidnapped her to try that he does not reveal it. At the same time, the Marcos family suffers again the nightmare of the disappearance of one of its members, which makes them forget their confrontations for a moment and reunite in grief.
Sierra and his team work around the clock to discover the identity of Cristina Marcos' kidnapper. For this, they do not have the testimony of the young woman who, in a state of shock after the events experienced, is unable to provide any definitive details to help resolve the case.
Five years after Patricia Marcos disappeared, Lieutenant Sierra teaches a class at the Civil Guard academy in which he reviews the keys to the case.